It could've been a disaster: The dispatcher gave clearance to a weed-spraying train to go forward when an unscheduled freight was passing through. "All I know is it wasn't kosher," dispatcher Dick Higgins said sheepishly. "I should've warned him it was coming."

Fortunately, there was no collision. But even if there had been, no lives or cargo would have been lost. This was, after all, just for fun, an evening with the Chesapeake Trainmasters Club, eight grown men playing with toy trains in a Brock Hall Estates basement.

They've been doing this nearly every Tuesday night now for 33 years, with four of the original 10 members still on board. The current roster of 12 ranges in age from 34 to 82. From different walks of life, they share a single passion: model trains.

It's not for real, but it is realistic. When they assemble for their two-hour sessions, it's also serious business. Each man is responsible for one section of HO-gauge track--controlling switches, coupling and uncoupling cars, even loading and unloading baggage at each stop with a pair of tweezers.

Members who mess up get demerits. Afterward, when they come together to socialize, whoever has the most sits by a bent spike; the one with the fewest gets the seat of honor by the golden spike.

They rotate among three suburban basements and layouts. One recent night, they were at Charlie Kilbourne's, running his Baltimore & Western line, which snakes around a 14-by-40-foot space from "Baltimore" at one end to "Cumberland" at the other.

It's all scheduled in advance, as if it were real life, with timetables that, as in real life, are sometimes problematic. Operators pick up "situation cards" at each stop, with instructions for loading or unloading freight, or adding or subtracting cars.

The timetables for 13 operating trains are written in chalk on blackboards. Helping the trainmen keep track of time are "fast clocks" at each station ticking away ten minutes in one. That allows for 20 "hours" of operation in the alloted two hours of real time.

This evening, there is less than a full crew. One man has called in sick, "as happens in the real world," notes Kilbourne, 71, a retired biology teacher at Prince George's Community College. Another is away. "These things happen," Kilbourne says with a shrug, adjusting his plans. Instead of four unscheduled freights, there will be two.

The Trainmasters do diesel trains one year, steam trains the next. They also alternate between "block control," in which scenery blocks each operator's view of other sections, and "walk-around" control," in which the hinged backdrops are half-raised so that the entire layout can be seen.

If this sounds complicated, it is. Just like real life.

And, just as in real life, "some nights it works perfectly," says Kilbourne, whose 12-page B&W Book of Rules is in effect. Leave a track turnout open, resulting in the misrouting of a scheduled train, and you get 20 demerits--and a good shot at the bent spike seat.

Kilbourne's layout is modeled roughly along the lines of the Western Maryland Railway and the B&O Railroad, and the tiny cars and figures and scenery are all designed to replicate the 1950s: from Baltimore's then-modest skyline, dominated by the Bromo Seltzer tower, to Cumberland's Queen City train station, now long gone.

Since 1966, the 200-foot B&W has grown in sophistication, though computerized it's not. Fast clocks came into use in 1968 and phones at each stop linked to the dispatcher in 1970. Both innovations were designed by Ron Schmidt, whose own Chesapeake Northwestern layout is part of the regular rotation.

In 1973, Kilbourne added "fly mail," tiny sacks of mail hung by the track and caught "on the fly" by passing trains.

The evening begins at 7:30 with a recap of last week's operation. Then the men take their stations. The first train leaves Baltimore at 4:30 p.m. It stops at Westminster, Thurmont, Green Spring, North Mountain, Hagerstown and Cumberland.

"It's my therapy night," says Tom Buckingham, who works for Giant Foods in his other life. Tonight his job is conductor for the mainline operated from the Baltimore end of the layout by Ron Schmidt. Buckingham's job is to follow his trains around the room, carrying out orders at each stop.

Approaching Westminster, Buckingham signals to Schmidt to bring the train to a stop. Then, as per his instructions, he separates one car and moves it to a siding.

"We've got work to do at Hagerstown," he says. There, using tweezers, he unloads mail from the mail car and loads more mail bound for Cumberland. This takes some time, and the train leaves Hagerstown two minutes (fast time) behind schedule.

"Okay, we should be able to pick up some speed now," he says, signaling to Schmidt to speed up the train. "All switches are good, so we have a straight shot to Cumberland."

At Cumberland, Buckingham waves to Schmidt to stop the train. "We're done on this trip, except unloading the mail and baggage. We've also got mail and baggage going out."

Buckingham has followed his train around the room to Baltimore, where he attempts to unload the mail, dropping it on the floor instead of the platform. "Oops," he says, picking it up.

Standing nearby, District firefighter Pat Kelly, who lives in Bowie and is the youngest member, says: "I never knew this aspect of railroading until I met these guys. I'm hoping someday I can have a layout like this.

"You get carried away. You start buying lanterns, tools of the road. My ex-wife got fed up with it because I bought too much stuff. My new girlfriend loves it. It's a great stress reliever for me. This can be hectic at times, but it's a challenge. Some of the older guys act like they're on the railroad."

Then it happens, up the line. "Whoa, whoa, whoa, Walter," says Ed Sylvia to Walt Silvester, who was running an unscheduled freight. "I didn't hear any orders for you to come through here."

"I had orders," Silvester insists.

"North Mountain," Sylvia says, identifying himself to the dispatcher, who is in another room unseen and unseeing, operating only by phone and schematics. "I didn't hear any orders."

"Yeah, you're right," says the dispatcher.

"Okay," says Sylvia, "he can come through now."

That's as bad as it gets, though when Schmidt blew the steam whistle just once at a visitor's request, dispatcher Higgins got on the phone demanding to know why in this world of diesel power it had sounded. Altogether, Higgins gave 42 orders. Two trains had run late, one early and the rest on time.

From his sequestered location, Higgins barks orders into a phone: "Okay, Westminster. He should be in by now, or just about there. Let me get Baltimore. Okay, Pat, I want you to back out on the main." And so it went.

For some, the highlight comes when the late night "mail catcher" makes its run from Cumberland to Baltimore, hooking the mail at each stop without stopping. At 11:26, fast time, the last train arrives back in Baltimore.

"That should do it," says Buckingham, its conductor.

"Number 4 got in," says Charlie Kilbourne.

"Yup, complete with both bags of mail," says Buckingham. "You get to keep the mail contract, Charlie."

CAPTION: A control panel for the Baltimore & Western Railroad. "Some nights it works perfectly," says Charlie Kilbourne.

CAPTION: Charlie Kilbourne, left, shows off one of his steam engines. Below is the schedule of trains leaving the Baltimore yard during a meeting of the Chesapeake Trainmasters Club in Kilbourne's basement.

CAPTION: Dispatcher Dick Higgins talks with an operator while scheduling a train. The dispatcher stays in another room, operating by phone and schematics.

CAPTION: A passenger train emerges from a tunnel, heading to the North Mountain depot. The schedule is made in advance.